Throttle positioner with dashpot



June 27, 1967 K. H. RHODES 3,327,695

THROTTLE POSITIONER WITH DASHPOT Filed Jan. 28, 1965 22 /2 -/50 /a@f/ifi? BY rg0 M4-M. vbzck.

United States Patent 3,327,695 THROTTLE PUSITIQNER WITH DASHIT Keith H.Rhodes, Racine, Wis., assigner to Walker Mannfacturing Company, acorporation of Delaware Filed Ian. 28, 1965, Ser. No. 428,648 6 Claims.(Cl. 12S-163) This invention relates to a positioning device for theVthrottle valve of an internal combustion engine, and more particularlyto a positioning device that reduces induction system vacuum upondeceleration and retards the rate of closing the throttle valve toprevent stalling.

In general, it is an object of the present invention to provide athrottle positioning device that is responsive to the induction systemvacuum to effect opening or cracking of the engine throttle valve duringdecelerating so that an unduly rich mixture will not be drawn into theengine cylinders and discharged into the atmosphere from `the exhaustsystem.

It is another object of the present invention to provide a throttlepositioning device of the above character that embodies an integraldashpot for retarding the rate of closing of the throttle valve toprevent engine stalling.

It is another object of the present invention to provide a throttlepositioning device of the aforementioned type that is entirely automaticin operation.

It is yet another object of the present invention to `provide a throttlepositioning device -that has a negligible effect on the fuel economy ofthe associated internal combustion engine.

It is a further object of this invention to provide a throttlepositioning device that may be used on a wide variety of engines.

It is yet another object of this invention to provide a throttlepositioning device that has an extremely simple construction and may beconveniently installed on an internal combustion engine.

A throttle positioning device for the throttle valve of an internalcombustion engine embodying this invention includes means responsive tothe pressure in the induction system posterior to the throttle valve formoving the throttle valve from a normal idle position to a partiallyopen position when the vacuum in the induction system is greater thanthe normal idle vacuum. Means are additionally provided for retardingthe rate of movement of the throttie valve from the partially openposition to the normal idle position when the induction system vacuumreturns to normal idle vacuum.

Other objects and advantages of the present invention will becomeapparent from the following detailed description taken in conjunctionwith the accompanying dra ing, wherein:

FIGURE 1 is a partial side elevational view of an internal combustionengine incorporating a preferred embodiment of this invention and,

FIGURE 2 is an enlarged cross sectional View of the throttle positioningdevice shown in FIGURE 1.

Referring now in detail to FIGURE 1 of the drawing, a throttlepositioning device, indicated generally by the reference numeral 10, isshown in operative association with an internal combustion engine 11.The internal combustion engine 11 has an induction system comprising anintake manifold 12 and a charge forming device in the form of acarburetor, shown partially at 14. The outlet of the carburetor 14registers with an upwardly extending inlet section 16 of the intakemanifold 12. A throttle plate 18 is pivotally supported within aninduction passage ice 19 of the charge forming device 14 by a throttlevalve shaft 20. A throttle control lever 21 is aixed to one end of theshaft 20. The depending end of the throttle control lever 21 ispivotally connected to a throttle control rod 22 that is actuated by anaccelerator pedal (not shown) by means of any suitable acceleratorlinkage. A throttle return spring 24 is connected vthrough a fitting orcoupling 26 to the throttle control rod 22 to urge the throttle linkageand throttle valve 18 ltoward the normal idle position, as illustratedin FIGURE 1.

The throttle positioning device 10 is rigidly attached to the engine 11through an appropriately shaped mounting bracket 28. The mountingbracket 28 is welded to another bracket 30 which is aixed to the engine11, as by bolts 32 and 34.

Referring now to FIGURE 2, it will be seen that the throttle positioningdevice 10 includes a valve housing, generally designated 36, that ispreferably fabricated of a die casting of a strong, light weightmaterial such as aluminum or the like. The housing 36 is generallycircular in cross section and is mounted on the side of an upwardlyextending section 38 of the mounting bracket 23 and is rigidly securedthereto by a plurality of circumferentially spaced screws 40 (only oneof which is illustrated) that extend through suitable apertures in thebracket section 38, the housing 36, and through an annular cup-shapedshell 42 that is attached to the bracket section 33 on the side oppositeto the housing 36. Suitable gaskets 43 are secured to the opposite sidesof the bracket section 38 to provide an air-tight seal between thehousing 36, the shell 42, and the bracket section 38.

An annular flange section 44 is formed around the periphery of the shell42 and is secured by a rolled seam or joint 46 to an annular flangesection 50 of a second cup-shaped shell 52. The space dened by theshells 42 and 52 forms a diaphragm chamber 54. An annular diaphragm 56,that is preferably constructed of a flexible and deformable materialsuch as synthetic rubber or the like, is secured within the chamber S4by compressing its outer periphery between the ange sections 44 and 50of the shells 42 and 52. It may be noted that the outer periphery of thediaphragm 56 acts as a gasket to provide an airtight seal between theflange sections 44 and 50 of the yshells 42 and 52.

The shell 52 is provided with a central opening defined by an annularoutwardly extending ange section 58. Press fitted within the flangesection 58 is a circular pull rod sleeve 0r guide 60 that is formed witha central bore 62. As illustrated in FIGURE 2, an elongated cylindricalpull rod 64, that extends through the bore 62, has a threaded inner endsection 65 extending into the diaphragm chamber 54. The pull rod endsection 65 extends through a central aperture 66 in the diaphragm 56,and the diaphragm 56 is secured to the end section 65 interjacent adiaphragm retainer ring 68 and an annular diaphragm retainer plate 70 bya nut '72 that is threaded on the end section 65.

The retainer ring 68 is formed with an annular concentric shouldersection 74 within which is seated one end of a helical spring 76. Theopposite end of the spring 76 bears against the guide 60 and iscoaxially disposed around the pull rod 64. It will be seen that theloading of the spring 76 between the retainer plate 70 and the guide 60yieldably maintains the diaphragm 56 and the pull rod 64 in theirrespective positions illustrated in the solid line view of FIGURE 2.

A plurlity of atmospheric vent holes 79 are formed in the shell 52 sothat the outer (right) side of the diaphragm 56 will be exposed toatmospheric pressure. It also will be seen that the diameter of the bore62 in the guide 60 is slightly larger than that adjacent portion of thepull rod 64 so that atmospheric air may freely flow around the rod 64and pass into the diaphragm chamber 54 between the shell 52 and thediaphragm 56.

The outer (right) end of the pull rod 64 is formed with a sleeve section80 within which one end of a pull cable 82 is rigidly fastened by `a setscrew 84. The opposite end of the cable 82 extends through and is freelyslidable within an opening in the coupling 26 (FIGURE 1). A throttlestop 83 is adjustably secured `on the outer end of the pull cable 82such that during engine decelerating conditions (when the acceleratorpedal is not depressed), longitudinal movement of the cable 32 towardsthe device will effect movement of both the throttle control lever 21and the throttle plate 18. During normal throttle operaton of theengine, the coupling 26 will overridethe cable 82 and throttle controlwill be maintained solely through longitudinal movement of the rod 22 inresponse to manual operation of the accelerator pedal. It will beapparent, of course, that a number of alternate forms of overriding typethrottle-control device linkages may be satisfactorily used and that thestructure herein described is merely exemplary insofar as such linkageconstructions are concerned.

Referring again to FIGURE 2, centrally formed in the valve housing 36 isan annular valve bore S6, one (right) end of which is formed with aconically shaped valve seat 88. Extending coaxially of the bore S6 andbeing reciprocable therewithin, is a valve member 90 that is formed witha frusto-conical end section 92 that is adapted to engage the valve seat88, thereby providing an air-tight seal between the diaphragm chamber 54and the interior of the valve housing 36. The valve member 90 is alsoformed with a medial section 94 onto which is threaded an annular springretainer cup 96. A valve spring 98, that is disposed around the valvemember l*medial section 94, extends between an annular recess 100 formedin the spring retainer cup 96 and an inwardly extending cylindricalsection 101 of the valve housing 36. It will be seen that the spring 98resiliently forces the retainer cup 96 away from the valve housingsection 78, thus yieldably maintaining the valve member end section 92engaged with the valve seat 88.

A flexible disk-shaped diaphragm 102, that is preferably fabricated fromthe same material as the diaphragm 56, is mounted on the side of thevalve housing 36 opposite the shells 42 and 52 by an annular cup-shapedcover plate 104 and a plurality lof circumferentially spaced screws 106that extend through the outer peripheral sections of the diaphragm 102and plate 104 and are screwed into the side of the valve housing 36. Thediaphragm 100 is formed with a central sleeve section 108 that defines acentral aperture 110 through which extends a cylindrical outer endsection 112 of the valve member 90. It may be noted that the diameter ofthe aperture 110 is slightly smaller than the valve section 112 so thatwhen it is inserted through the aperture 110, an air-tight seal isprovided between the diaphragm 102 and the valve member 90. The coverplate 104 also is formed with a central opening 114 and a plurality ofair bleed holes 11S, the latter of which communicate atmospheric air toan annular chamber 116 defined by the cover plate 104 and the diaphragm102. The outer end of the valve section 112 protrudes through thecentral opening 114 and it will be seen that the opening `114 issufficiently large to permit air to ow to and from the chamber 116around the valve section 112.

A diametrically extending slot 118 is formed in the outer end of thevalve section 112 and a suitable tool such as a screwdriver or the -likemay be inserted therein to rotate the valve 90 and thereby adjust therelative axial position of the spring retaining cup 96 along thethreaded valve medial section 94. Also provided on the outer end of thevalve section 112 is a retaining ring 120 that is preferably of thesnap-on type and is adapted to limit the axial inward movement of thevalve member 90.

An atmospheric vent passage 122 extends radially through the valve body36 so that atmospheric air may enter the diaphragm chamber S4 on theleft hand side of the diaphragm 56. The vent passage 122 has arestricted orifice 124 between its ends, however, -to restrict the airtiow to and from the diaphragm chamber 54.

Mounted on the side of the intake manifold 12 is a fitting 128 (FIGUREl) that communicates the interior of the manifold 12 posterior to thethrottle valve 18 with one end of a flexible vacuum line 130. Theopposite end of the vacuum line 130 is stretched around the outer end ofla hollow tube 132 that is press fitted within a suitable bore 134formed in the top of the valve housing 36. It will thus be seen that themanifold vacuum existing within the intake manifold 12 will betransmitted through the vacuum line 130 and the tube 132 to the interiorof the valve housing 36.

Operation The throttle positioning device 10 is secured lby brackets 28and 38 to the automotive engine in a location that will allow the pullcable 82 a straight pull on the fitting 26, and the position of the stop83y is adjusted such that the cable 82 is taut `when the engine throttleplate 18 is in its closed or hot idling position and the diaphragm is inits extreme right hand position as shown in the dotted line view ofFIGURE 2. When the engine is idling, the position of the retainer cup 96is adjusted Vby rotating the valve 90 such that the tension of thespring 98 is just sufficient tov maintain the valve section 92 engagedwith the valve seat 88.

When the manifold Vacuum increases within the manifold 12, 'as occursupon deceleration of the engine, the internal pressure within the valvehousing 36 will decrease, whereby the atmospheric pressure presentwithin the chamber 116 will exceed the pressure within the valve housing36 and the diaphragm 102 will be forced in- Wardly, thereby biasing thecup 96 inwardly and unseating the valve member 90.

As the valve becomes unseated, the air within the diaphragm chamber 54is transferred through the valve bore 86, the interior of the valvehousing 36 and out through the tube 132 and vacuum line 130, therebyeffecting a partial vacuum within the chamber 54. The atmospheric ventpassage 122 will limit the actual vacuum that is produced within thediaphragm chamber, of course. Atmospheric pressure, which iscommunicated to the outer (right) side of the diaphragm 56 through thebore 62 and the bleed holes 79, and the action o-f the spring 76, thenbias the diaphragm 56 and the retainer plate 70 inwardly to draw thepull rod 64 inwardly through the guide 60. This effects a correspondinginward movement of the pull cable 82. As the cable 82 moves, the lowerend of the throttle control lever 21 is rotated clockwise with thethrottle shaft 20 thereby partially opening or cracking the throttleplate 18. The opening of the throttle plate 18 limits the manifoldvacuum within the manif-old 12 and, accordingly, reduces the vacuum uponthe idle discharge circuit of the carburetor 14. This reduces theemission of unburned hydrocarbons from the engine exhaust upondeceleration.

When the automotive engine reaches an idling condition or begins toaccelerate, the vacu-um within the manifold 12 and the interior of thevalve housing 36 is relieved, whereby the spring 98 biases the cup 96 tothe left and reseats the valve 90. As the valve 90 becomes seated, thevacuum within the chamber 54 is relieved by virtue of atmospheric airpassing into the chamber 54 through the air vent passage 122 and thethrottle return spring 24 acting through the cables S2 returns thediaphragm S6 to the dotted line position illustrated in FIGURE 2.

The throttle positioning device also may function as an antistalldashpot in the following manner. When the throttle-valve 18 is openthrough the throttle actuating linkage including the throttle actuatingrod 22, the tension upon the cable 82 is released. The throttle returnspring 24, therefore, will no longer act upon the diaphragm 56 throughthe pull rod 64. The coil spring 76 then urges the diaphragm 56 to thesolid line position shown in FIGURE 2. When this occurs, air is drivenfrom the diaphragm chamber 54 through the atmospheric vent passage 122.If the throttle valve 18 is rapidly closed by relieving pressure uponthe accelerator pedal, tension is again exerted -upon the cable 82. Thespring 24 then tends to compress the spring 76, which is weaker or has alower rate. The diaphragm 56 is then drawn toward the dotted lineposition. 'Ihe rate of movement of the diaphragm 56 and the pull rod 64-is reduced, however, because its rapid movement tends to create apartial vacuum within the diaphragm chamber 54 because of the restrictedorifice 124 in the atmospheric vent passage 122. The size of the orifice124 will determine the rate at which the diaphragm S6 may return to thedotted line position. It should be readily apparent that this actiondelays the rate of closing of the throttle valve 18 so that stalling ofthe engine may be precluded.

While it will be apparent that the preferred embodiment hereinillustrated is well calculated to fulfill the objects stated, it will beappreciated that the present invention is susceptible to modification,variation and change without departing from the proper scope and fairmeaning of the subjoined claims.

What is claimed is:

1. A combined fluid motor and dashpot for controlling a throttle valveof an internal combustion engine induction system comprising anexpansible fluid chamber defined in part by a movable Wall, said wallbeing adapted to be operatively connected to the throttle valve formovement to a iirst position when the throttle valve is in a normal idleposition and a normal pressure exists in said fluid chamber, biasingmeans for exerting a force upon said wall tending to move said wall fromsaid first position to a second position, said biasing means beingincapable of moving said wall from its rst position to its secondposition when the throttle -valve is in the normal idle position and thenormal pressure exists in said ii-uid chamber and capable of moving saidwall from its rst position t-o its second position when the throttlevalve is opened beyond a predetermined partially opened position, fluidpressure responsive means responsive to the vacuum in the nductionsystem posterior to the throttle valve for altering the pressure withinsaid fluid chamber from said normal pressure for 4movement of said wallfrom said iirst position to a second position wherein the throttle valveis moved to the predetermined partially opened position when the vacuumexceeds normal idle vacuum, and means for returning the pressure withinsaid chamber to said normal pressure at a restricted rate when theinduction system vacuum is at least equal to normal idle vacuum forretarding the movement of said wall from said second position to saidfirst position to retard the closing of the throttle valve.

2. A combined iiuid motor and dashpot for controlling a throttle valveof an internal combustion engine induction system comprising anexpansible iiuid chamber defined in part by a movable wall, firstbiasing means for urging said wall to a first position, second biasingmeans for biasing said Wall to a second position, said first biasingmeans being stronger than said second biasing means whereby said wall isnormally biased to said first position, said wall being adapted to beoperatively connected to the throttle valve and being in said rstposition when the throttle valve is in a normal idle position, and uidpressure responsive means responsive to induction system vacuum foraltering the pressure within said chamber for moving said wall from saidfirst position to a second position wherein the throttle Valve ispartially open when the induction system vacuum exceeds normal idlevacuum, said second biasing means being effective to move said wall fromsaid first position to said second position when the throttle valve isopen a greater extent that the partially open position, and means forreturning the pressure within said chamber to a normal pressure at arestricted rate when the induction system pressure is at least equal tonormal idle vacuum and the throttle valve is moved to the normal idleposition for `retarding the movement of the throttle valve from thepartially open position to the idle position.

3. A combined tiuid motor and -dashpot for controlling a throttle valveof an internal combustion engine induction system comprising anexpansible fluid chamber deiined in part by a diaphragm, said diaphragmbeing adapted to to be operatively connected to the throttle valve,first biasing means for urging said diaphragm to a first positionwherein the throttle valve is in a normal idle position, second biasingmeans for biasing said diaphragm to a second position wherein thethrottle valve is in a partially opened position, said first biasingmeans being stronger than said second biasing means whereby saiddiaphragm is normally biased to said first position, means including apressure responsive valve for exposing said fiuid chamber to inductionsystem Vacuum when the induction system vacuum is greater than normalidle vacuum for moving said diaphragm from said first position to saidsecond position to partially open the throttle valve to reduce thevacuum in the induction system, said second biasing means beingeiiective to move said ydiaphragm from said lirst position to saidsecond position when the throttle valve is open a greater extent thanthe partially opened position, and venting means for normally ventingsaid uid chamber to atmospheric pressure, said venting means offering asubstantially greater resistance to iiow than said first named means forrestricting rate of movement of said `diaphragm from said secondposition to said first position to retard the movement of the throttlevalve from the partially opened position to the normal idle position.

4. An internal combustion engine comprising an induction system, athrottle valve for controlling the fiow through said induction system, acombined iiuid motor and dashpot for controlling said throttle valvecomprising an expansible fluid chamber, defined in part by a diaphragm,linkage means operatively connecting said diaphragm to said throttlevalve, first biasing means for urging said throttle valve to a normalidle position and said ydiaphragm to a first position, second biasingmeans for biasing said Idiaphragm to a second position, and saidthrottle valve to a partally opened position, said first biasing meansbeing stronger than said second biasing means whereby said diaphragm isnormally biased to said first position, means including a pressureresponsive valve for exposing said iiuid chamber to induction systemvacuum when the induction system vacuum is greater than normal idlevacuum for moving said diaphragm from said first position to said secondposition to partially open said throttle valve to reduce the vacuum inthe induction system, said linkage means including a lost motion devicefor relieving said diaphragm from the action of said first biasing meanswhen said throttle valve is opened past said partially opened position,said second biasing means being effective to move said diaphragm fromsaid first position to said second position when said throttle valve isopen a greater extent than said partially opened position, and ventingmeans for normally venting said fluid chamber to atmospheric pressure,said venting means offering a substantially greater resistance toV fiowthan said first named means for restricting rate of movement of saiddiaphragm from said second position to said yfirst position to retardthe movement of said throttle valve from the 7 partially opened positionto the normal idle position under References Cited the `acti-ori of saidfirst biasing means. UNITED STA E PATE TS 5. A combined fluid motor anddashpot as set forth in T s N claim 1 wherein the uid pressureresponsive means com- 2,005,262 5/1935` Liverance L 123 103- prises apressure responsive valve. 5 3,027,884 4/1962 Baie 123-97 6. A combinedfluid motor and ydashpot as set forth in t A claim 1 wherein the meansfor returning thel pressure MARK NEWMAN Primm?) Examm'er' Within thechamber to the normal pressure at a restricted .RALPH D, BLAKESLEE,Examiner.

rate comprises a normally opened atmospheric vent.

1. A COMBINED FLUID MOTOR AND DASHPOT FOR CONTROLLING A THROTTLE VALVEOF AN INTERNAL COMBUSTION ENGINE INDUCTION SYSTEM COMPRISING ANEXPANSIBLE FLUID CHAMBER DEFINED IN PART BY A MOVABLE WALL, SAID WALLBEING ADAPTED TO BE OPERATIVELY CONNECTED TO THE THROTTLE VALVE FORMOVEMENT TO A FIRST POSITION WHEN THE THROTTLE VALVE IS IN A NORMAL IDLEPOSITION AND A NORMAL PRESSURE EXISTS IN SAID FLUID CHAMBER, BIASINGMEANS FOR EXERTING A FORCE UPON SAID WALL TENDING TO MOVE SAID WALL FROMSAID FIRST POSITION TO A SECOND POSITION, SAID BIASING MEANS BEINGINCAPABLE OF MOVING SAID WALL FROM ITS FIRST POSITION TO ITS SECONDPOSITION WHEN THE THROTTLE VALVE IS IN THE NORMAL IDLE POSITION AND THENORMAL PRESSURE EXISTS IN SAID FLUID CHAMBER AND CAPABLE OF MOVING SAIDWALL FROM ITS FIRST POSITION TO ITS SECOND POSITION WHEN THE THROTTLEVALVE IS OPENED BEYOND A PREDETERMINED PARTIALLY OPENED POSITION, FLUIDPRESSURE RESPONSIVE MEANS RESPONSIVE TO THE VACUUM IN THE INDUCTIONSYSTEM POSTERIOR TO THE THROTTLE VALVE FOR ALTERING THE PRESSURE WITHINSAID FLUID CHAMBER FROM SAID NORMAL PRESSURE FOR MOVEMENT OF SAID WALLFROM SAID FIRST POSITION TO A SECOND POSITION WHEREIN THE THROTTLE VALVEIS MOVED TO THE PREDETERMINED PARTIALLY OPENED POSITION WHEN THE VACCUMEXCEEDS NORMAL IDLE VACUUM, AND MEANS FOR RETURNING THE PRESSURE WITHINSAID CHAMBER TO SAID NORMAL PRESSURE AT A RESTRICTED RATE WHEN THEINDUCTION SYSTEM VACUUM IS AT LEAST EQUAL TO NORMAL IDLE VACUUM FORRETARDING THE MOVEMENT OF SAID WALL FROM SAID SECOND POSITION TO SAIDFIRST POSITION TO RETARD THE CLOSING OF THE THROTTLE VALVE.